Variability of the Deepwater Horizon Surface Oil Spill Extent and Its Relationship to Varying Ocean Currents and Extreme Weather Conditions - Mathematical Modelling and Numerical Simulation of Oil Pollution Problems - page 14

(a)

(b)

( c )

Fig. 1.5 a Time series of thewind direction and intensity. b Time series of the daily area (in 10 3 km 2 )
covered by surface oil as obtained from the Marine Pollution Surveillance Reports (MPSRs). A
three-day running test on the presence of oil was applied to minimize the impact of partial satellite
coverage. Red circles denote the estimated values, while the blue line shows the results of a cubic
spline fit to these values. The numbers in the white circles indicate the day of the month. The blue
circles indicate the dates in which maps of surface currents and surface oil spill extent are shown
in Fig. 1.4 . c Cumulative oil area during April-August, 2010. Colours indicate the number of days
the oil slick was present in the daily MPSRs

predominant winds during Alex had the potential to cause the oil to move and con-
centrate in more westerly locations, enhance dispersion, or simply drive oil ashore
predominantly along the barrier islands of the Mississippi Sound. The areal extent
of the oil immediately after the passage of Hurricane Alex exhibited a reduction of
approximately 28 10 3 km 2 , a value of more than half the pre-hurricane surface oil

extent (Figs. 1.5 b and 1.6 ). Winds from Tropical Depression Bonnie on July 24-25,
2010, contributed partly to this temporary apparent decrease in surface oil extent.
The limits of the main surface oil area extended south to approximately 27 ⓦ N
86 ⓦ W during May 16-28, 2010, and east to approximately 85 ⓦ W28 ⓦ N during May

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